U.S. patent application number 14/176562 was filed with the patent office on 2015-04-30 for method and system for streamer redundancy.
This patent application is currently assigned to PGS Geophysical AS. The applicant listed for this patent is PGS Geophysical AS. Invention is credited to Geir Andre Motzfeldt Drange, Oyvind Hillesund.
Application Number | 20150121124 14/176562 |
Document ID | / |
Family ID | 51870807 |
Filed Date | 2015-04-30 |
United States Patent
Application |
20150121124 |
Kind Code |
A1 |
Hillesund; Oyvind ; et
al. |
April 30, 2015 |
METHOD AND SYSTEM FOR STREAMER REDUNDANCY
Abstract
Streamer redundancy. At least some illustrative embodiments are
methods including: in a streamer towed by a survey vessel, sensing
a first interconnection of a daisy chain the first interconnection
between a first networked unit and a second networked unit, wherein
the first networked unit and the second networked unit comprise a
portion of a plurality of networked units; and determining that a
fault condition exists on the first interconnection in response to
the sensing; disabling the first interconnection responsive to the
fault condition; enabling a second interconnection responsive to
the fault condition, wherein the second interconnection couples the
first networked unit and a third networked unit of the plurality of
networked units and wherein the second interconnection does not
couple to the second networked unit; and reporting information
indicative of the fault condition to the survey vessel via the
second networked unit.
Inventors: |
Hillesund; Oyvind; (Nesbru,
NO) ; Drange; Geir Andre Motzfeldt; (Borgen,
NO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PGS Geophysical AS |
Oslo |
|
NO |
|
|
Assignee: |
PGS Geophysical AS
Oslo
NO
|
Family ID: |
51870807 |
Appl. No.: |
14/176562 |
Filed: |
February 10, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61897533 |
Oct 30, 2013 |
|
|
|
Current U.S.
Class: |
714/5.1 |
Current CPC
Class: |
G01V 3/17 20130101; G06F
11/0745 20130101; G01V 1/22 20130101; G01V 1/38 20130101 |
Class at
Publication: |
714/5.1 |
International
Class: |
G06F 11/07 20060101
G06F011/07 |
Claims
1. A method comprising: in a streamer towed by a survey vessel, the
streamer comprising a first, second and third networked unit:
sensing a first interconnection of a daisy chain the first
interconnection being between the first networked unit and the
second networked unit, and determining that a fault condition
exists on the first interconnection in response to the sensing;
disabling the first interconnection responsive to the fault
condition; and enabling a second interconnection responsive to the
fault condition, wherein the second interconnection couples the
first networked unit and the third networked unit, and wherein the
second interconnection does not couple to the second networked
unit.
2. The method of claim 1 wherein the first interconnection
comprises a telemetry interconnection and the fault condition
comprises a telemetry fault condition on the telemetry
interconnection.
3. The method of claim 1 wherein the first interconnection further
comprises a power interconnection, and the fault condition
comprises a power fault condition on the power interconnection.
4. The method of claim 1 further comprising reporting information
indicative of the fault condition to a recording system on the
survey vessel.
5. The method of claim 1 further comprising: sensing the second
interconnection; determining that a fault condition exists on the
second interconnection in response to the sensing; disabling the
second interconnection responsive to the fault condition; and
enabling a third interconnection, wherein: the streamer comprises a
fourth networked unit, the third interconnection couples the first
networked unit and the fourth networked unit, and the third
interconnection does not couple to the second networked unit and
does not couple to the third networked unit.
6. A system comprising: a streamer configured to be towed behind a
survey vessel; a first networked unit deployed in the streamer; a
second networked unit deployed in the streamer; a third networked
unit deployed in the streamer; wherein a first output port of the
first networked unit is coupled to a first input port of the second
networked unit; wherein a first output port of the second networked
unit is coupled to a first input port of the third networked unit;
wherein a second output port of the first networked unit is coupled
to a second input port of the third networked unit; and wherein the
first networked unit is configured to communicate with the third
networked unit on the second output port of the first networked
unit, if a telemetry fault condition occurs between the first and
second networked units, and to communicate with the second
networked unit on the first output port of the first networked unit
otherwise.
7. The system of claim 6, wherein the telemetry fault condition
comprises at least one failure selected from the group consisting
of: a failure of the second networked unit; a failure of a
communicative connection between the first output port of the first
networked unit and the first input port of the second networked
unit; and a failure of a communicative connection between the first
output port of the second networked unit and the first output port
of the third networked unit.
8. The system of claim 6, wherein the first networked unit is at
least one selected from the group consisting of: a telemetry unit;
a power unit; a sensor digitizing unit; and an auxiliary unit.
9. The system of claim 7 further comprising: a sensor, wherein when
the first networked unit comprises a telemetry unit, and the sensor
is coupled to the telemetry unit; and wherein the telemetry unit
communicates data received from the sensor.
10. The system of claim 9 further comprising a sensor digitizing
unit coupled to the sensor; and wherein the telemetry unit receives
sensor data in digitized form from the sensor digitizing unit.
11. The system of claim 9 wherein the sensor is at least one
selected from the group consisting of: seismic survey sensors;
accelerometers, hydrophones; geophones; electric field sensors;
magnetic field sensors; and electromagnetic survey sensors.
12. A streamer comprising: an outer surface; a rope disposed within
the outer surface; a communication pathway disposed within the
outer surface; a sensor disposed within the outer surface; a
telemetry unit coupled to the sensor via a sensor digitizing unit
and configured to transmit data received from the sensor to a
survey vessel via the communication pathway; a first networked unit
having a coupling between a first output port of the telemetry unit
and an input port of the first networked unit, wherein the coupling
is configured to selectably connect the first output port of the
telemetry unit and the input port of the first networked unit; a
second networked unit having a coupling between a second output
port of the telemetry unit and an input port of the second
networked unit, wherein the coupling is configured to selectably
connect the second output port of the telemetry unit and the input
port of the second networked unit; and a control unit connected to
the coupling between the first output port of the telemetry unit
and the input port of the first networked unit, and configured to
sense a telecommunication fault condition thereon, wherein the
control unit is configured disable the coupling between the first
output port of the telemetry unit and the input port of the first
networked unit and enable the coupling between a second output port
of the telemetry unit and an input port of the second networked
unit if a communications fault occurs between the telemetry unit
and first networked unit.
13. The system of claim 12 wherein the coupling between the first
output port of the telemetry unit and the input port of the first
networked unit further comprises a power interconnection configured
to transmit electrical power between the first output port of the
telemetry unit and the input port of first networked unit, and
wherein the control unit is further configured to sense a power
fault condition on the power connection.
14. The system of claim 13 wherein the coupling between the second
output port of the telemetry unit and the input port of the second
networked unit further comprises a power interconnection configured
to transmit electrical power between the second output port of the
telemetry unit and the input port of the second networked unit, and
wherein the control unit is further configured to disable the power
interconnection between the first output port of the telemetry unit
and the input port of the first networked unit and enable the power
interconnection between the second output port of the telemetry
unit and the input port of the second networked unit if a power
fault condition occurs between the telemetry unit and first
networked unit.
15. The system of 12 further comprising a sensor digitizing unit
coupled to the sensor and the telemetry unit, and configured to
digitize data received from the sensor.
16. The system of claim 12 wherein the sensor is at least one
selected from the group consisting of: seismic survey sensors, and
electromagnetic survey sensors.
17. The system of claim 12 further comprising: a third networked
unit, the third networked unit having a coupling between a third
output port of the telemetry unit and an input port of the third
networked unit, wherein the coupling is configured to selectably
connect the third output port of the telemetry unit and the input
port of the third networked unit; and wherein the control unit is
connected to the coupling between the second output port of the
telemetry unit and the input port of the second networked unit and
is further configured to sense a telemetry fault condition
thereon.
18. The system of claim 17 wherein the control unit is further
configured to disable the coupling between the second output port
of the telemetry unit and the input port of the second networked
unit and enable the coupling between the third output port of the
telemetry unit and an input port of the third networked unit if a
telemetry fault condition is detected on the coupling between the
second output port of the telemetry unit and the input port of the
second networked unit.
19. The system of claim 17 wherein: the between the first output
port of the telemetry unit and an input port of the first networked
unit further comprises a power interconnection configured to
transmit electrical power between the first output port of the
telemetry unit and the input port of first networked unit, the
coupling between the second output port of the telemetry unit and
an input port of the second networked unit further comprises a
power interconnection configured to transmit electrical power
between the second output port of the telemetry unit and the input
port of second networked unit; the coupling between the third
output port of the telemetry unit and an input port of the third
networked unit further comprises a power interconnection configured
to transmit electrical power between the third output port of the
telemetry unit and the input port of third networked unit; and
wherein the control unit is further configured to sense a power
fault condition on the power interconnection between the second
output port of the telemetry unit and the input port of second
networked unit.
20. The system of claim 19 wherein the control unit is further
configured to disable the power interconnection between the second
output port of the telemetry unit and the input port of the second
networked unit and enable the selectable power interconnection
between the third output port of the telemetry unit and an input
port of the third networked unit if a power fault condition is
detected on the power interconnection between the second output
port of the telemetry unit and the input port of the second
networked unit.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application Ser. No. 61/897,533 filed Oct. 30, 2013 and titled
"Method for Streamer Redundancy", which provisional application is
incorporated by reference herein as if reproduced in full
below.
BACKGROUND
[0002] Seismic and electromagnetic surveys may be two common types
of geophysical survey. Geophysical survey equipment typically
includes complex apparatus containing various components and
connections. For example, a streamer commonly used in geophysical
survey operation typically contains many sensors, sensor digitizing
units, telemetry units, power units, navigation units, control
units, and/or auxiliary units. All of these units are connected to
a control/recording system onboard of a survey vessel, by way of
one or multiple telemetry and power connections. When one of these
units fails during operation, replacing the faulty unit (or "failed
unit") may result in operating downtime, increased operating
cost/time and other inefficiencies. Thus, systems and methods that
mitigate downtime arising from the replacement of faulty devices in
the streamer would provide a competitive advantage in the
marketplace.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] For a detailed description of exemplary embodiments,
reference will now be made to the accompanying drawings in
which:
[0004] FIG. 1 shows an overhead view of a marine survey system in
accordance with at least some embodiments;
[0005] FIG. 1A shows portions of the marine survey system of FIG. 1
in further detail.
[0006] FIG. 2 shows a block diagram of a set of networked units in
accordance with at least some embodiments;
[0007] FIG. 3 shows a block diagram of a control unit in accordance
with at least some embodiments;
[0008] FIG. 4 shows a flow chart of a method in accordance with at
least some embodiments;
[0009] FIG. 5 shows a block diagram of a set of networked units in
accordance with at least some embodiments;
[0010] FIG. 6 shows a block diagram of a control unit in accordance
with at least some embodiments; and
[0011] FIG. 7 shows a flow chart of a method in accordance with at
least some embodiments.
NOTATION AND NOMENCLATURE
[0012] Certain terms are used throughout the following description
and claims to refer to particular system components. As one skilled
in the art will appreciate, different companies may refer to a
component by different names. This document does not intend to
distinguish between components that differ in name but not
function. In the following discussion and in the claims, the terms
"including" and "comprising" are used in an open-ended fashion, and
thus should be interpreted to mean "including, but not limited to .
. . . " Also, the term "couple" or "couples" is intended to mean
either an indirect or direct connection. Thus, if a first device
couples to a second device, that connection may be through a direct
connection or through an indirect connection via other devices and
connections.
[0013] "Cable" shall mean a flexible, load carrying member that
also comprises electrical conductors and/or optical conductors for
carrying electrical power and/or signals between components.
[0014] "Rope" shall mean a flexible, axial load carrying member
that does not include electrical and/or optical conductors. Such a
rope may be made from fiber, steel, other high strength material,
chain, or combinations of such materials.
[0015] "Line" shall mean either a rope or a cable.
[0016] "Downstream" as used herein means, in the context of the
relationship between daisy chain units, such units disposed in the
direction of, or more proximal to, the survey vessel.
[0017] "Upstream" as used herein means, in the context of the
relationship between daisy chain units, such units disposed in the
direction opposite of, or more distal to, the survey vessel.
[0018] "Daisy chain" means, in the context of an interconnection
between devices, an interconnection in which signals or power, as
the case may be, are transmitted end-to-end through each device so
interconnected.
[0019] "Networked unit" means a device deployed in a streamer and
having input and output ports configurable to couple to a daisy
chain interconnection. Examples of networked units include sensor
digitizing units, telemetry units power units, navigation units
control units and auxiliary units.
[0020] "Exemplary, as used herein, means "serving as an example,
instance, or illustration." An embodiment described herein as
"exemplary" is not necessarily to be construed as preferred or
advantageous over other embodiments.
DETAILED DESCRIPTION
[0021] The following discussion is directed to various embodiments
of the invention. Although one or more of these embodiments may be
preferred, the embodiments disclosed should not be interpreted, or
otherwise used, as limiting the scope of the disclosure or the
claims. In addition, one skilled in the art will understand that
the following description has broad application, and the discussion
of any embodiment is meant only to be exemplary of that embodiment,
and not intended to intimate that the scope of the disclosure or
the claims, is limited to that embodiment.
[0022] FIG. 1 shows an overhead view of a marine survey system 100
in accordance with at least some embodiments. In particular, FIG. 1
shows a survey vessel 102 having onboard equipment, herein referred
to collectively as recording system 104, such as navigation, energy
source control, and data recording equipment. Survey vessel 102 is
configured to tow one or more streamers 106A-F through the water.
While FIG. 1 illustratively shows six streamers 106, any number of
streamers 106 may be used.
[0023] The sensor streamers 106 are coupled to towing equipment
that maintains the streamers 106 at selected depth and lateral
positions with respect to each other and with respect to the survey
vessel 102. The towing equipment may comprise two paravane tow
lines 108A and 108B each coupled to the vessel 102 by way of
winches 110A and 1108, respectively.
[0024] Electrical and/or optical connections between appropriate
components in the onboard recording system 104, and components on
the streamers 106, such as sensors 116 may be made using inner
lead-in cables 126A-F via networked units 109 as described further
herein below and in conjunction with FIGS. 2 and 3.
[0025] In a seismic survey, sensors 116 may include one or more
instruments such as hydrophones, geophones or accelerometers to
detect seismic signals. In an electromagnetic survey, sensors 116
may include electric field detector, a magnetic field detector or a
combination electric field and magnetic field detector.
[0026] In either type of survey, a substantial number of sensors
116 may be interconnected via a communication pathway along a
length of a streamer 106, which may, in some embodiments reach
lengths of tens of kilometers. The sensors 116 may be accompanied
by networked units 109 which may include telemetry units as well as
power, navigation, control, and auxiliary units. Sensors 116 and
networked units 109 may be disposed within an outer surface 107,
FIG. 1A, of streamers 106, in which communication pathway 125 and
rope 127 may also be disposed. In some embodiments, outer surface
107 may be distinguished by an outer jacket at least partially
covering streamer 106; by way of example, polyurethane jackets,
mesh jackets, or impermeable jackets with cutouts distributed along
the length of streamer 106. Rope 127 may be provided as a strength
member. These networked units may be connected to recording system
104 by one or more telemetry and/or power connections coupled
together in "daisy chain" fashion. For example, as described
further in conjunction with FIG. 2, data from sensors 116 may be
digitized by a sensor digitizing unit and provided to telemetry
units in digital form. The digitized data may then be modulated
onto a carrier for example, which may then be transmitted to
recording system 104. The telemetry signals may be transmitted to
the survey vessel 102 via the daisy-chained telemetry connections.
Networked units 109 may also include auxiliary units and power
units. Power units may supply conditioned power to other networked
units 109. Although networked units 109 are illustrated within
streamers 106, in some embodiments networked units may span
multiple streamer sections, and in still other embodiments a single
networked unit may span an entire length of a streamer. Further, in
some embodiments, networked units may be located in connector
modules between streamer sections, and in other embodiments
networked units may be located in connector modules in some
locations of the streamer and embedded or otherwise enclosed within
the streamer in other locations of the streamer.
[0027] FIG. 2 illustrates a block diagram of a portion 200 of a set
of such networked units, comprising telemetry units 202A-C, power
unit 204 and auxiliary unit 206. Telemetry units 202A-C may receive
data from sensors 116 via sensor digitizing units 210A-D and may
communicate the data to the shipboard recording system 104. Power
units 204 may provide controlled power to other networked
units.
[0028] Telemetry units 202A-C may receive data from sensors 116 via
sensor digitizing units 201A-D may and communicate data to the
shipboard recording system 104. Telemetry units may communicate
such data in digital form. Telemetry units 202A-C are shown coupled
to sensors 116A-H via sensor digitizing units 210A-D. In at least
some embodiments sensor digitizing units 210A-D may include an
analog-to-digital converter (ADC). In still other embodiments,
sensor digitizing units 210A-D may be data acquisition computer,
field programmable gate arrays or the like. In some embodiments the
ADCs may be implemented as integrated in the telemetry units, and
in yet other embodiments the sensor digitizing units may be
implemented as discrete units as illustrated in FIG. 2. The sensor
digitizing units may be coupled to the telemetry units
electrically, optically or by any other suitable interface. In at
least some embodiments, sensor digitizing units 210A-D may be
coupled to the telemetry units via a daisy chain interconnection.
While, for the purpose of illustration three sensors are shown
coupled to sensor digitizing unit 210A, two sensors coupled to each
of sensor digitizing units 210B and 210D, and a single sensor
coupled to sensor digitizing units 210C, in an embodiment of a
streamer 106, a sensor digitizing unit may be coupled to and
receive data from one to about twelve sensors. In some embodiments,
a sensor digitizing unit may couple to as many as 32 sensors. In
any case, the specific number of sensors coupled to a sensor
digitizing unit is not limiting, and any number of sensors may, in
principle, be coupled to a sensor digitizing unit. Similarly, for
the purpose of illustration, each of telemetry units 202A-B are
depicted as being coupled to a single sensor digitizing unit, 210A
and 210B respectively, and telemetry unit 202C is depicted a being
coupled to two sensor digitizing unit s, 210C and 210D. In an
embodiment of sensor streamer 106, each telemetry unit may be
coupled to and receive data from as many as about twenty-four to
about one hundred digitizing units. However, the specific number of
sensor digitizing units coupled to a telemetry unit is not
limiting, and any number of sensor digitizing units may, in
principle, be coupled to a telemetry unit.
[0029] The digitized data may then be provided to modulators 212A-C
which may modulate the digitized data onto a carrier for
transmission to the onboard recording equipment. Examples of
modulation which may be used include frequency shift keying (FSK),
phase shift keying (PSK) quadrature amplitude modulation (QAM),
quadrature phase shift keying (QPSK) or discrete multi-tone
(DMT).
[0030] For the purpose of illustration, assume that telemetry unit
202C represents a device proximal to the survey vessel and
telemetry unit 202A represents a device distal to the survey
vessel. Telemetry signals from a telemetry unit, say telemetry unit
202A may be transmitted toward the recording system 104 and pass
through the downstream telemetry units 202B and 202C. Failure of
one of these telemetry units, or a connection therebetween, could
prevent the telemetry data from telemetry unit 202A from reaching
the survey vessel. Thus, the daisy-chained networked units may be
coupled by bypass interconnections which provide for bypassing such
a failed networked unit or connection, in accordance with the
principles now described in further detail.
[0031] In the illustrated embodiment, each of the networked units
includes two input ports and two output ports. In some embodiments,
the input ports may be configured to connect to telemetry,
communications or data channels, and in at least some embodiments,
the ports may be configured to connect to power transmission lines
or buses. And in still other embodiments, the ports may be
configured to connect to both telemetry, communications or data
channels and power transmission channels. Telemetry unit 202A
includes daisy chain input port 214A and daisy chain output port
216A. Likewise, telemetry unit 202B comprises daisy chain input
port 214B and daisy chain output port 216B, power unit 204
comprises daisy chain input port 214C and daisy chain output port
216C, telemetry unit 202C includes daisy chain input port 214D and
daisy chain output port 216D, and auxiliary unit 206 comprises
daisy chain input port 214E and daisy chain output port 216E. Daisy
chain interconnection 218A coupling daisy chain output port 216A of
telemetry unit 202A to daisy chain input port 214B of telemetry
unit 202B and similar daisy chain interconnections 218B, 218C and
218D also comprise a daisy chain interconnection between the
respective networked units, namely telemetry unit 202B, power unit
204, telemetry unit 202C and auxiliary unit 206. A second set of
interconnections, 220A, 220B and 220C, provide a bypass path to
allow routing around a faulty networked unit or daisy chain
connection. Thus, bypass interconnection 220A couples output port
217A of telemetry unit 202A to input port 215C of power unit 204.
Likewise, bypass interconnection 220B couples output port 217B of
telemetry unit 202B to input port 215D of telemetry unit 202C and
interconnection 220C couples output port 217C to input port 215E of
auxiliary unit 206. Bypass interconnections 220D and 220E provide
similar redundant paths coupling input port 215B and output port
217D to networked units upstream and downstream of portion 200 (not
shown in FIG. 2), respectively. In this way, a failure of, for
example, telemetry unit 202B, or the daisy chain interconnections,
218A, 218B therebetween, may be bypassed via bypass interconnection
220A. On detection of such failure condition by telemetry unit
202A, telemetry unit 202A may enable bypass interconnection 220A,
and communication may then proceed toward recording system 104.
Similarly, output port 217E may provide a bypass interconnection
for auxiliary unit 206 to networked units downstream of portion
200, and input port 215A may provide a bypass interconnection to
networked units upstream of portion 200. In some embodiments,
interconnections may be electrical and communication via electrical
signals. In other embodiments, interconnections may be optical and
communications by optical signals and in yet other embodiments,
combination thereof may be used. In still other embodiments any
suitable communication method may be used. Further, daisy chain
interconnections 218A-D and bypass interconnections 220A-E may also
carry electrical power as well as telemetry signals, as set forth
above. Although an exemplary failure has described above in terms
of a telemetry signal failure, a failure of a daisy chained power
connection or unit coupled to such a power connection may also be
similarly bypassed via bypass interconnections 220A-E.
[0032] Power unit 204 may be included to provide power to other
networked units. Networked units connected to power unit 204, such
as telemetry unit 202C, may receive electrical power via power unit
204, and power unit 204 may control the state of the electrical
power supplied to the networked units daisy chained with power unit
204. Thus, if a failure occurs in such a networked unit, a for
example a short circuit or power consumption in excess of a
predetermined specification, power unit 204 may detect the anomaly
and disable the power to the failed unit. However, in this case, as
described above, daisy chained units both upstream and downstream
of the malfunctioning unit would also lose power.
[0033] Alternatively, by enabling a bypass interconnection, a power
unit 204 may bypass a malfunctioning networked unit and maintain
power to at least units that are otherwise daisy chained with the
malfunctioning unit. For example, if telemetry unit 202C fails
whereby its current consumption exceeds a predetermined
specification, power unit 204 may disable daisy chain
interconnection 218C. Power unit 204 may also enable bypass
interconnection 220C, thereby bypassing telemetry unit 202C, and
continue to supply power to networked units downstream of telemetry
unit 202C, such as auxiliary unit 206. Although bypass
interconnection 220C has been described in conjunction with
supplying power to networked units, as previously described bypass
interconnection 220C may also transport daisy chained communication
signals between telemetry units 202 and the survey vessel 102, for
example. Such communication signals may, in at least some
embodiments, be bidirectional. Power unit 204 may also detect a
malfunction of a daisy chained telemetry signal, and bypass daisy
chain interconnection 218C and select redundant bypass
interconnection 220C.
[0034] An interconnection controller within a networked unit may be
used to detect malfunction on a daisy chain interconnection and
select a bypass interconnection to bypass the malfunction. In the
exemplary embodiment of telemetry units 202, power unit 204 and
auxiliary unit 206 include an interconnection controller 222 which
may monitor the daisy chain interconnections 218 for fault
conditions and change between the daisy chain interconnections and
bypass interconnections 220 accordingly. A fault condition on an
interconnection may arise from an anomaly in a downstream networked
device or on, for example, a power or telemetry channel between
networked units.
[0035] This may be further understood by referring now to FIG. 3,
showing a block diagram of an exemplary interconnection controller
222 in accordance with an embodiment. Interconnection controller
222 may include an interconnection enable unit 302, telemetry fault
detector 304, a power fault detector 306 and an interconnection
controller 308. Interconnection enable unit 302 may connect daisy
chain input port 214 to one of daisy chain output port 216 or
output port 217 based on the state of the downstream
interconnections and/or devices. Further, input signals and power
may be received on either daisy chain input port 214 or input port
215 depending on the state of upstream interconnections or devices.
In other words, an upstream device may have itself bypassed a
faulty intervening unit or connection to reach the particular
device including interconnection controller 222. Input sense
circuitry 310 may detect which of input ports 214 and 215 is active
in that it is receiving telemetry and/or power from an upstream
unit. For example, input sense circuitry 310 may detect the
presence of power on one of input ports 214 and 215. In at least
some embodiments, input sense circuitry may detect telemetry data
on the active one of daisy chain input port 214 and input port 215.
In some embodiments, telemetry units (such as units 202, FIG. 2)
may provide a heartbeat signal at a predetermined interval which
may be detected by input sense circuitry 310. Such a heartbeat
signal may be used in embodiments where telemetry but not power is
provided in a daisy chain configuration, and particularly in such
embodiments where telemetry data rates are low, whereby a change in
input ports by an upstream device may otherwise escape detection.
Input sense circuitry 310 may connect the active input port to node
312 which may be input to output select circuitry 314.
[0036] Connection controller 308 may select the state of output
select circuitry 314 in response to signals received from telemetry
fault detector 304 and power fault detector 306. If daisy chained
downstream devices or interconnections are free of fault
conditions, both telemetry fault detector 304 and power fault
detector 306 may provide respective output signal values to
connection controller 308 in a first predetermined state denoting a
fault-free condition on the daisy chain interconnection downstream.
Connection controller 308 may then set a first predetermined value
on control line 316 whereby output select circuitry 314 connects
node 312 to daisy chain output port 216. Conversely, if either of
telemetry fault detector 304 or power fault detector 306 determines
that a downstream fault condition exists on the daisy chain
interconnection, the respective one of telemetry fault detector 304
and power fault detector 306 may provide an output signal having a
predetermined value denoting a fault condition exists in the daisy
chain interconnection. Connection controller 308 may then set a
second predetermined value on control line 316 whereby output
select circuitry 314 connects node 312 to output 317, thereby
enabling the bypass interconnect and disabling the daisy chain
interconnect. Output select may connect node 312 to output 317 by,
for example in at least some embodiments, electronic switches,
optical switches or address table remapping, or any other suitable
means as may be reflected by the communication pathway
architecture.
[0037] For example, power fault detector 306 may monitor the daisy
chain power interconnection for an overcurrent condition. Such a
condition may represent a short circuit or other failure occurring
in the device downstream of the particular networked unit sensing
the overcurrent condition. Connection controller 308 may then
signal output select circuitry 314 to select output port 217
thereby bypassing the failed device. In at least some embodiments,
power fault detector 306 may employ a Hall effect current sensor to
sense the current in the daisy chain power interconnections.
[0038] Similarly, telemetry fault detector 304 may monitor the
daisy chain telemetry interconnection for a loss of telemetry
signal. In particular, the telemetry fault detector may monitor the
telemetry interconnection for upstream telemetry communications
from survey vessel 102. A loss of upstream communication for a
predetermined interval of time may be indicative of a failure in a
downstream telemetry unit. In at least some embodiments, telemetry
units (such as telemetry units 202, FIG. 2) may send a beacon or
heartbeat signal which may be used by telemetry fault detector 304
to sense a fault condition on daisy chain telemetry
interconnections. In such embodiments, a loss of the heartbeat
signal may be indicative of a fault condition. In response to a
telemetry interconnection fault condition, connection controller
308 may then signal output select to connect to output port 217, as
previously described.
[0039] Because a fault condition may be detected locally, the site
of the failed unit or daisy chain interconnection may be
determined. Thus, in an embodiment, connection controller 308 may
be coupled to a telemetry unit, such as a telemetry unit 202, and
reporting information indicative of the detected fault to survey
vessel 102, for example via the telemetry unit. Such information
may include information identifying the particular connection
controller, a serial number for example. The reported information
may then be used to locate the faulty unit or daisy chain
connection which may facilitate repair of the streamer including
the faulty unit.
[0040] In the exemplary embodiment of FIG. 2, the interconnection
controller (e.g. interconnection controller 222, FIG. 2) is shown
disposed within the networked units themselves. In at least some
embodiments interconnection controllers may be deployed in a
separate control unit, however the principles of operation would be
substantially unaffected by the form of deployment.
[0041] FIG. 4 shows a flow chart of a method 400 for bypassing a
networked unit in accordance with an example embodiment. The method
starts in block 402 and in block 404, the method determines if a
telemetry fault condition is detected on the telemetry daisy chain
interconnection. A telemetry fault condition may be detected in
block 404 as described in conjunction with FIG. 3. If no telemetry
fault condition has been detected, block 404 falls through the "No"
branch to block 406. In block 406, method 400 determines if a power
fault condition is detected on the power daisy chain
interconnection. A power fault condition may be detected in block
406 as described above in conjunction with FIG. 3. If no power
fault condition is detected, block 406 falls through the "No"
branch to return to block 404 wherein method 400 continues to
monitor the state of the daisy chain interconnections.
[0042] Returning to blocks 404 and 406, if either a telemetry fault
condition is detected (block 404) or a power fault condition is
detected (block 406) on the daisy chain interconnections, the
blocks fall through the respective "Yes" branch, depending on the
type of fault condition detected. And, in block 408, the daisy
chain interconnection may be disabled by bypassing it. In at least
some embodiments, block 404 may bypass the daisy chain
interconnection as described above in conjunction with FIGS. 2 and
3. In block 410, information indicative of the fault condition is
reported to the survey vessel. Such information may include a
serial number or other identifier of the unit bypassed, or an
analogous identifier of the reporting unit, and the nature of the
fault condition (e.g. telemetry, power) which information may be
logged and used to facilitate repair of the streamer. Method 400
ends at block 410.
[0043] Refer now to FIG. 5 showing a block diagram of a portion 500
of a set of networked units in accordance with another embodiment.
Portion 500 includes networked units 502A-E, which may comprise
telemetry units, power units, sensor digitizing units, and
auxiliary units as previously described. Networked units 502A-E may
be interconnected in daisy chain fashion via input ports 504 and
output ports 506 having interconnections 508 therebetween. Further
networked units 502A-E may be selectably interconnected via bypass
interconnections 510 and 512, as described in further detail below
in conjunction with FIG. 6.
[0044] Bypass interconnections 510 may connect two networked units
502, bypassing an intervening unit in the daisy chain
configuration. Thus, for example interconnection 510A may couple an
output port 511A of networked unit 502A to an input port 509C of
networked unit 502C, bypassing networked unit 502B. Similarly,
interconnection 510B may connect output port 511B of networked unit
502B to input port 509D of networked unit 502D, bypassing networked
unit 502C. Bypass interconnection 510C may connect output port 511C
of networked unit 502C to input port 509E of networked unit 502E
bypassing networked unit 502D. Bypass interconnection 510M may
connect input port 509B of networked unit 502B to a device (not
shown) upstream of portion 500. Similarly input port 509A of
networked unit 502A may be connected to a device upstream of
portion 500. Bypass interconnect 512D may connect output port 511D
of networked unit 502D to a device downstream (not shown) of
portion 500.
[0045] Portion 500 also may include a second set of bypass
interconnections 512. Bypass interconnections 512 may connect two
networked units 502 while bypassing two intervening networked units
in the daisy chain configuration. For example, bypass
interconnection 512A couples output port 507A of networked unit
502A to input port 505D of networked unit 502D, bypassing networked
units 502B, C. In similar fashion, interconnection 512B couples
output port 507B of networked unit 502B to input port 505E of
networked unit 502E, bypassing networked units 502C, D. Bypass
interconnections 512C, D may connect output ports 507C and 507D
502C, D, respectively to networked units (not shown) downstream of
portion 500. Bypass interconnections 512M, N may connect input
ports 505B, C of units 502B, C, respectively to networked units
(not shown) upstream of portion 500. Input port 505A of networked
unit 502A may likewise connect via a bypass interconnection to a
networked unit (not shown) upstream of portion 500.
[0046] The disabling of a daisy chain interconnection by the
enabling of a bypass interconnection may be controlled by an
interconnection controller 520. In the exemplary embodiment of FIG.
5, interconnection controllers 520 are shown as disposed within
networked units 502. However, in other embodiments, interconnection
controllers 520 may be deployed in a separate control unit. In
still other embodiments, a portion of interconnection controllers
520 may be disposed within some networked units 502 and another
portion may be deployed in separate control units.
[0047] Turning to FIG. 6, an interconnection controller 520 in
accordance with an embodiment is shown in further detail.
Interconnection controller 520 includes an interconnection enable
unit 602, a telemetry fault detector 604, power fault detector 606
and interconnection controller 608. Interconnection enable unit 602
includes an input sense circuitry 610 and output select unit 614.
The operation of input sense circuitry 610 may be similar to the
operation of input sense circuitry 310, FIG. 3. However, input
sense circuitry 610 senses daisy chain input port 504 and bypass
input ports 505 and 509 to determine which input port is active, as
described above. The active input port is connected to node
612.
[0048] Telemetry fault detector 604 and power fault detector 606
may be similar to telemetry fault detector 304 and power fault
detector 306 described above in conjunction with FIG. 3. However,
in the embodiment of interconnection controller 520, these devices
may be connected both to daisy chain output port 506, via lines
613A, B, respectively, but also to bypass interconnection output
port 511, via lines 615A,B, respectively. Thus, if a fault
condition on the daisy chain interconnection is sensed by one or
both of telemetry fault detector 304 and power fault detector 606,
interconnection controller 608 may signal output select unit 614 to
enable the bypass interconnection through bypass output port 511.
Recall, a bypass interconnection via an output port 511 may bypass
a single unit in the daisy chain configuration. If, however a pair
of units, for example, have failed or otherwise present a fault
condition, enabling output port 511 may not clear the fault
condition. In that case, one or both of telemetry fault detector
604 and power fault detect unit 606, depending on the type of fault
condition, may continue sense the fault condition on output port
511 via lines 615, and maintain its fault assertion with respect to
interconnection controller 608. Interconnection controller 608 may
then signal output select unit 614 to disable the interconnection
via bypass output port 511 and enable the bypass interconnection
via output port 507 (e.g. a bypass 512, FIG. 5). In this way, a
failure of two units in a daisy chain configuration that have
failed may be bypassed.
[0049] This may be further understood by referring to FIG. 7,
illustrating a flow chart of a method 700 for disabling a networked
unit in accordance with an example embodiment. The method starts in
block 702 and senses the daisy chain interconnection output port
(e.g. an output port 506), block 703. In block 704, the method
determines if a telemetry fault condition is detected on the
telemetry daisy chain interconnection. A telemetry fault condition
may be detected in block 704 as described in conjunction with FIG.
3. If no telemetry fault condition has been detected, block 704
falls through the "No" branch to block 706. In block 706, method
700 determines if a power fault condition is detected on the power
daisy chain interconnection. A power fault may be detected in block
706 also as described above in conjunction with FIG. 3. If no power
fault condition is detected, block 706 falls through the "No"
branch to return to block 704 wherein method 400 continues to
monitor the state of the daisy chain interconnections.
[0050] Returning to blocks 704 and 706, if either a telemetry fault
condition is detected (block 704) or a power fault condition (block
706) on the daisy chain interconnections, the blocks fall through
the respective "Yes" branch, depending on the type of fault
condition detected. In block 708, method 700 branches depending on
which of the output ports is being sensed. If the daisy chain
interconnection is being sensed, block 708 falls through the "Yes"
branch and in block 710 the daisy chain interconnection is bypassed
via the first bypass interconnection (e.g. via an output port 511),
thereby disabling it. In at least some embodiments, the first
bypass may be enabled as described in conjunction with, inter alia,
FIG. 6. Method 700 then senses the bypass interconnection enabled
in block 710, block 712. In block 713, information indicative of
the fault condition is reported to the survey vessel. Such
information may include a serial number or other identifier of the
unit or units bypassed, or an analogous identifier of the reporting
unit, and the nature of the fault (e.g. telemetry, power) which
information may be logged and used to facilitate repair of the
streamer. Method 700 returns to block 704 to determine if the fault
is cleared in response to the bypassing of the downstream unit. If
a fault condition is not cleared, i.e. the fault condition remains,
one of blocks 704 and 706 fall through its respective "Yes" branch
to block 708. Because the bypass interconnection is being sensed
via block 712, block 708 proceeds by the "No" branch to block 714.
In block 714, the second bypass interconnection is enabled (e.g.
via an output port 507). In at least some embodiments, the second
bypass may be enabled as described in conjunction with, inter alia,
FIG. 6. In block 716, information indicative of the fault condition
is reported to the survey vessel, similarly to block 713. Method
700 ends at block 718.
[0051] References to "one embodiment", "an embodiment", "a
particular embodiment", and "some embodiments" indicate that a
particular element or characteristic is included in at least one
embodiment of the invention. Although the phrases "in one
embodiment", "an embodiment", "a particular embodiment", and "some
embodiments" may appear in various places, these do not necessarily
refer to the same embodiment.
[0052] The above discussion is meant to be illustrative of the
principles and various embodiments of the present invention.
Numerous variations and modifications will become apparent to those
skilled in the art once the above disclosure is fully appreciated.
For example, the principles disclosed herein may be applied to
embodiments wherein N+1 connections may be used to bypass N faulty
units and/or interconnections, or combinations thereof. It is
intended that the following claims be interpreted to embrace all
such variations and modifications.
* * * * *